3.4 engine swap (Page 1/6)
Mr.sandman JUN 14, 06:39 AM
Hello everyone ,I am new to the fiero ! I am picking up a 1987 Pontiac fiero 2.8 automatic this weekend ,and I am going to do the 3.4 liter engine swap .the 2.8 has rod Knock.I just have a couple questions, some may have already been answered ,but rather then rummaging threw the fourm I figured I'd just ask . I know about the starter relocation kit .I am just curious if I also need to replace the flywheel /flexplate even though I am mateing it back to the stock automatic transmission . Do i need one off of an 88? or will the flywheel off the 3.4 or 2.8 work .the 3.4 is from a 94 -95 Camaro. Also what other modifications will I need to do. I am already aware of using the timing cover and oil pan from the 2.8 and as mentioned before the starter relocation Kit and reusing the lower intake and upper intake manifolds from the 2.8 as well as the exhaust manifolds 17lb injectors harmonic balancer , distributor, modifying the baffle in the oil pan to fit the new pickup. I've also seen that some people just bash in the corner of the fiero oil pan to clear the engine mount ... I would rather not do this I'm sure there is another way? I appreciate any and all information I can receive!
Thanks in advance !
fierofool JUN 14, 08:46 AM
You will need a flex plate from an 88 or from a Beretta or Cavalier, Buick Skylark, Grand Am or other 88 and above 60 degree V6 engine. I think up through a '93 will work.

You can use the oil pan from the 3.4. I have it in my 87 GT. I don't think my installer had to dent the pan. I was thinking that was a requirement only on the 88. You won't have to notch the baffles with the 3.4 pan. Not sure about the timing cover, though the one from either engine will mate with either oil pan. My 3.4 didn't have the timing cover on it when I picked it up, so my 2.8 cover was used.

Some discounters like Rock Auto, Parts Geek, Parts Train or Parts Direct may still have new flex plates available.

You can use the 2.8 harmonic balancer or if you want to use the 3.4, match-cut the timing mark over to the 3.4
Dragonfish JUN 14, 09:53 AM
Everything you need to know here

http://fiero34swap.eleventenths.org/
Dennis LaGrua JUN 14, 10:47 AM
The 3.4L P/R swap is about the easiest swap that you can do. Your Fiero will run better and give a boost in performance but a chip reprogram is recommended to adjust to the larger flow rate of the 3.4L injectors.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Mr.sandman JUN 14, 11:28 AM
okay so everything seems pretty straightforward then. the only thing I am now concerned with is computer tuning. this is something I was not aware of .this car won't necessarily be a daily driven car but I would like it to be reliable how much does it cost to get the computer reprogrammed.and where would I do that? I am talking the option that does not require me to completely replace the ECM and do a bunch of wiring
Mr.sandman JUN 14, 11:30 AM
Also thank you all so much for the very quick responses I'm excited about this new project and have always wanted a fiero! It's even the year I was born!! This will also be my fifth Pontiac! I've owned .

[This message has been edited by Mr.sandman (edited 06-14-2019).]

fierofool JUN 14, 11:47 AM
I have other information in my thread on Georgia Fieros, including gasket set numbers and updated fuel injector information that doesn't require ECM reprogramming.

http://www.gafiero.org/bbs/index.php?topic=2080.0
Will JUN 14, 05:55 PM

quote
Originally posted by fierofool:

You will need a flex plate from an 88 or from a Beretta or Cavalier, Buick Skylark, Grand Am or other 88 and above 60 degree V6 engine. I think up through a '93 will work.

You can use the oil pan from the 3.4. I have it in my 87 GT. I don't think my installer had to dent the pan. I was thinking that was a requirement only on the 88. You won't have to notch the baffles with the 3.4 pan. Not sure about the timing cover, though the one from either engine will mate with either oil pan. My 3.4 didn't have the timing cover on it when I picked it up, so my 2.8 cover was used.

Some discounters like Rock Auto, Parts Geek, Parts Train or Parts Direct may still have new flex plates available.

You can use the 2.8 harmonic balancer or if you want to use the 3.4, match-cut the timing mark over to the 3.4




Fiero oil pan repros available new... I installed one on my Formula summer last year.
Will JUN 14, 05:57 PM

quote
Originally posted by Mr.sandman:

Hello everyone ,I am new to the fiero ! I am picking up a 1987 Pontiac fiero 2.8 automatic this weekend ,and I am going to do the 3.4 liter engine swap .the 2.8 has rod Knock.I just have a couple questions, some may have already been answered ,but rather then rummaging threw the fourm I figured I'd just ask . I know about the starter relocation kit .I am just curious if I also need to replace the flywheel /flexplate even though I am mateing it back to the stock automatic transmission . Do i need one off of an 88? or will the flywheel off the 3.4 or 2.8 work .the 3.4 is from a 94 -95 Camaro. Also what other modifications will I need to do. I am already aware of using the timing cover and oil pan from the 2.8 and as mentioned before the starter relocation Kit and reusing the lower intake and upper intake manifolds from the 2.8 as well as the exhaust manifolds 17lb injectors harmonic balancer , distributor, modifying the baffle in the oil pan to fit the new pickup. I've also seen that some people just bash in the corner of the fiero oil pan to clear the engine mount ... I would rather not do this I'm sure there is another way? I appreciate any and all information I can receive!
Thanks in advance !



Not so sure how well the TH125 will stand up to the extra torque from a 3.4. It's not a stout transmission. Has anyone done this before?
Dennis LaGrua JUN 14, 08:11 PM

quote
Originally posted by Will:


Not so sure how well the TH125 will stand up to the extra torque from a 3.4. It's not a stout transmission. Has anyone done this before?



I've met a few owners running the 3.4L with the TH125 w/o issues. The step up in torque with a 3.4L P/R engine is 200ft lbs and only 30 ft lbs more than the 2.8L.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "